Tetracycline Chemistry and Reactivity

Strong acids and strong bases attack TC with a hydroxyl group on C6 causing a loss in activity through modification of the C ring.

At pH less than 2, TC eliminates a molecule of water with concomitant aromatization of ring C forming the more energetically favored resonant system of the naphthalene group found in the inactive anhydrotetracyclines.

Bases promote a reaction between the 6-OH group and the ketone group at the 11-position, causing the bound between the 11 and 11a atoms to cleave forming the lactone ring found in the inactive isotetracycline.

<p>Anhydrotetracycline differs from TC in both molecular and structural formula and is inactive as an antibacterial.</p> Signup and view all the answers

<p>The base colorimetric method is used for Tetracycline and Oxytetracycline since the addition of alkali to their solutions produces a yellow color having an absorption maximum at 380 nm, while Chlortetracycline gives a yellow color that rapidly disappears and gives practically no absorption at 380 nm.</p> Signup and view all the answers

<p>The disadvantage of the method is that the reading of absorbance should be within exactly 6 minutes after the addition of the alkali because there is a slow but definite decrease in absorbance with time (Intensity of color decreases with time).</p> Signup and view all the answers

<p>Isotetracycline has the same molecular formula as TC but different structural formula and it is inactive.</p> Signup and view all the answers

<p>The structural difference between TC and Isotetracycline results in Isotetracycline being inactive as an antibacterial agent.</p> Signup and view all the answers